Muscles Of Posteior Abdominal Wall

Question 1

What is the mnemonic for the muscles of the posterior abdominal wall?

Answer 1

I Quite Like PiMMs
(Iliacus, Quadratus lumborum, Psoas Major/Minor )

Question 2

List the Muscles in the posterior abdominal wall compartment

Answer 2

1.) Iliacus
2.) Quadratus Lumborum
3.) Psoas Major
4.) Psoas Minor

Question 3

List the Origins and Insertions for these muscles

Answer 3

1.) Iliacus
O: iliac fossa
I: Lesser trochanter of femur

2.) QL
O: iliolumbar ligament + posterior iliac crest
I: inferior border of 12th rib + TVP’s of L1-L4

3.) Psoas Major
O: Vertebral bodies, discs and TVP’s of T12-L4
I: Lesser trochanter of femur

4.) Psoas Minor
O:Lateral surface of bodies of T12-L1
I: Pectineal Line + iliopectineal eminence + iliac fossa

Question 4

What Nerves innervate this region?

Answer 4

1.) Femoral n
2.) lumbar plexus
3.) branch from L1

Question 5

What is the only muscle to be innervated from the femoral nerve in this region?

Answer 5

Iliacus

Question 6

What is the only muscle to be innervated by a branch from L1?

Answer 6

Psoas minor

Question 7

What two muscles are innervated by the lumbar plexus?

Answer 7

Psoas major
Quadratus lumborum

Question 8

What muscle is missing in 60% of cadavers?

Answer 8

Psoas minor

Question 9

What two muscles do hip flexion?

Answer 9

Iliacus
Psoas Major

Question 10

What muscle does spine extension and lateral flexion?

Answer 10

Quadratus lumborum

Question 11

What muscle will flex the trunk if the thigh is fixed?

Answer 11

Psoas Major

Question 12

What do Iliacus and Psoas major have in common?

Answer 12

They are both hip flexors

Question 13

What is the only muscle in this compartment that does not cross the hip joint and therefore provides no action at the hip?

Answer 13

Psoas minor